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Velocity Time Integral is a clinical Doppler ultrasound measurement of blood flow, equivalent to the area under the velocity time curve. The product of VTI (cm/stroke) and the cross sectional area of a valve (cm2) yields a stroke volume (cm3/stroke), which can be used to calculate cardiac output.
A RSBI score of less than 65 [3] indicating a relatively low respiratory rate compared to tidal volume is generally considered as an indication of weaning readiness. A patient with a rapid shallow breathing index (RSBI) of less than 105 has an approximately 80% chance of being successfully extubated, whereas an RSBI of greater than 105 virtually guarantees weaning failure. [4]
From these, it is easy to calculate the area (in cm 2) of the aortic valve by simply dividing the LV stroke volume (in cm 3) by the AV VTI (in cm) measured on the spectral Doppler display using continuous-wave Doppler. [citation needed] Stroke volume = 0.785(π/4) x Diameter 2 x VTI of LVOT Cross sectional area of LVOT = 0.785(π/4) x LVOT ...
Integrated pulmonary index (IPI) is a patient pulmonary index which uses information from capnography and pulse oximetry to provide a single value that describes the patient's respiratory status. IPI is used by clinicians to quickly assess the patient's respiratory status to determine the need for additional clinical assessment or intervention.
In respiratory physiology, the ventilation/perfusion ratio (V/Q ratio) is a ratio used to assess the efficiency and adequacy of the ventilation-perfusion coupling and thus the matching of two variables: V – ventilation – the air that reaches the alveoli; Q – perfusion – the blood that reaches the alveoli via the capillaries
Mandatory minute ventilation (MMV) (also called minimum minute ventilation) is a mode of mechanical ventilation which requires the operator to determine what the appropriate minute ventilation for the patient should be and the ventilator then monitors the patient's ability to generate this volume. If the calculation suggests the volume target ...
Major factors influencing cardiac output – heart rate and stroke volume, both of which are variable. [1]In cardiac physiology, cardiac output (CO), also known as heart output and often denoted by the symbols , ˙, or ˙, [2] is the volumetric flow rate of the heart's pumping output: that is, the volume of blood being pumped by a single ventricle of the heart, per unit time (usually measured ...
Impedance cardiography (ICG) is a non-invasive technology measuring total electrical conductivity of the thorax and its changes in time to process continuously a number of cardiodynamic parameters, such as stroke volume (SV), heart rate (HR), cardiac output (CO), ventricular ejection time (VET), pre-ejection period and used to detect the impedance changes caused by a high-frequency, low ...